Abstract:

Geographical variation of body color is widely present in reptile populations that survive in different substrate habitats, multiple potential mechanisms can account for this color variation. Phrynocephalus versicolor and P. frontalis, close genetic relatives, constitute a phylogenetic species group together with P. przewalskii. In this study, a fiber spectrophotometer (AvaSpec-2048) was used to record the skin luminous reflectivity of 12 sites across the lizard’s body, and we quantitatively compared the natural color variation of dark P. versicolor and light P. frontalis that lived in “melanistic” and “non-melanistic” habitats, respectively. We aimed to determine whether the color variations of both populations were time reversible, and further discuss potential mechanisms that substrate color may have on color variation of Phrynocephalus lizards. Our results showed that the body color of P. versicolor in “melanistic” habitat was significantly darker than P. frontalis in the “non-melanistic” withered yellow habitat. We also conducted a reciprocal transplantation experiments (i.e. “non-melanistic” withered yellow P. frontalis individuals were transplanted and fed in “melanistic” substrate environment, while “melanistic” P. versicolor individuals were transplanted and fed in withered yellow substrate environment). For “melanistic” P. versicolor, the skin reflectivity of six sites increased significantly after one week, while no significant changes were detected in other sites. For “non-melanistic” P. frontalis, except the skin reflectivity of two sites (left hind limb and top right on the back) significantly changed, compared to corresponding values one week previously, other sites showed no significant changes. Our results suggest that P. versicolor possesses stronger color variation ability than P. frontalis, and the color phenotypes are likely inherited in both species. Short-term changes of substrate color can cause slightly color variations that are difficult to distinguish by naked eyes, suggesting ontogeny related hereditary factors may also play a controlling role.

Key words: melanistic, body color variation, Phrynocephalus, skin reflectivity